In recent years, increase in a capacity of an inverter serving as a power converter has been demanded. In order to increase the capacity, it is necessary to connect IGBTs (Insulated Gate Bipolar Transistors) which are power semiconductor elements or freewheeling diodes in parallel.
However, in the case where power semiconductor modules including power semiconductor elements such as IGBTs or diodes are connected in parallel, it is problematic in that an imbalance of current flowing through the power semiconductor elements connected in parallel occurs due to an imbalance of parasitic resistance or parasitic inductance in power wirings of the power semiconductor elements. Output current tends to be concentrated on a power semiconductor element in which a parasitic resistance or a parasitic inductance of a power wiring is small, and therefore a life and reliability of the power semiconductor element may be reduced.
Regarding the above problem, for example, PTL 1 discloses a technique for achieving equal output current by having an equal impedance in power wirings connecting power semiconductor elements. PTL 2 discloses a structure for correcting a current imbalance and reducing a surge voltage by having equal current flowing through switching elements and minimizing a conductor connecting the switching elements.